Scrolling from Capazitive Keyboard not working - qt.labs.controls

Tried with Qt 5.6 Beta Gallery example (ScrollBar) and own code

I'm using BlackBerry PRIV (Android 5.1.1) which is a slider where the physical keyboard is a capazitive keyboard where you can swipe and normally android apps then are scrolling up/down in lists, large pages, webview and more out of the box - per ex. from GMail app, PlayStore, Fotos, ...

there are two blogs describing HowTo deal with the keyboard from android apps, where the second one describes the capazitive keyboard:
http://devblog.blackberry.com/2015/11/ready-set-type-developers-guide-to-the-priv-keyboard-part-1/
http://devblog.blackberry.com/2015/11/ready-set-type-developers-guide-to-the-priv-keyboard-part-2/

perhaps I have to add more to the qt.labs.controls as ScrollBar{} ?
tried to set focus: true - didn't help

the keyboard itself was correctly recognized by Qt 5.6:
opening the slider - the virtual keyboard disappears and closing it reappears.